Electrical controller.



PATENTED OCT. 23, 1906.

D. LARSON. ELECTRICAL CONTROLLER.

APPLICATION FILED NOV. 4, 1905.

2 SHEETS-SHEET 1.

WITNESSES:

ATTORNEY PATENTED OUT. 23, 1906.

D. LARSON.

ELECTRICAL CONTROLLER.

APPLIOATION FILED NOVA, 1905.

2 SHEETS-SHEET 2.

INVENTOR BY 5W ATTORNEY WITNESSES.

rns NORRIS PETERS cc, wasnmcmu. I:v c.

DAVID LARSON, OF YONKERS, NEW YORK.

ELECTRICAL CONTROLLER.

Specification of Letters Patent.

Patented Oct. 23, 1906.

Application filed November 4:, 1905. Serial NO. 285,836.

To all LU/b01771 it Tmay concern.-

Be it known that 1, DAVID LARSON, a subject of the King of Sweden, and aresident of the city of Yonkers, in the county of VVestchester and Stateof New York, have invented certain new and useful Improvements inElectrical Controllers, of which the following is a specification.

My invention relates to electrical controllers for use with eitherdirect or alternating currents; and it consists in the construction andarrangement of parts herein shown and described and the novel featureswhereof are set forth in claims.

Referring to the drawings, Figure 1 is a diagrammatic representation ofan electric motor, an electrical controller, and certain electricalconnections which are used in carry ing out my invention. Fig. 2 is amodifica tion showing the invention applied to an alternating-currentmotor. Figs. 3 and 4 illustrate modifications of certain details.

Like characters of reference designate corresponding parts in all of thefigures.

designates an electric motor.

and 21 designate mains from a suitable source of electrical supply ofpractically constant pressure or voltage. These may pass through fuses22 and a manually-operated main-line switch 23 and then by conductors 24and 25 to other apparatus, which will be pointed out later.

3O designates a base, of slate or other suitable material, upon whichthe various parts of the controller maybe mounted.

31 designates a reversing-switch. It comprises two magnets 40 and 50.These two magnets are substantially alike in construction, so that Iwill describe but one of them specifically.

41 designates a magnet-frame, preferably constructed of laminatedmagnetic material.

42 is a coil or Winding arranged to energize the magnet, and 43 is thecore or armature of the magnet.

Four insulated movable contacts 44, 45, 46, and 47 are connected by arod 43 and cross-arms 43 and 43 to move with core 43 until they comeinto contact with corresponding stationary contacts 44", 45, 46, and. 47Magnet 50 comprises similar parts.

Above magnets 40 and 50 a horizontal arm 32 may be placed, pivoted at 33and pro vided with an operating-handle 34. A rod 35, attached to core43, extends upward and terminates in a pro ection 35 within a slot 36 inarm 33. A similar rod 37 is attached to core 52, and this terminates ina projection 37 A within slot 38 in the other end of the arm 32. Springs39 39 may be provided to keep the arm 32 and its connected parts intheir central or off position.

designates a manually-operated controlswitch or master-switch. Itcomprises an arm 61, pivoted. at 62, which has carried upon butinsulated from it two contact-plates 63 and 64. Contact-plate 63 bearsupon stationary segmental contact 65 and is arranged to be moved to theleft or right to connect the latter either to stationary contact 66 orstationary contact 67. Contact-plate 64 bears upon stationary segmentalcontact 63 and is arranged to be moved to the left or right to connectthe latter with one or another of a series of stationary contacts 69,which are connected together through a re sistance 69.

Before proceeding farther with the description of the apparatus I willtrace out some of the electrical circuits and describe the operation ofthe parts already described.

It may be seen that the minus main 21 is connected by conductors 24 and24 to stationary segmental contact 63 on switch 60. If an operator movesarm 61 to the left, contact-plate 63 will connect stationary con tacts65 and 66, and a circuit will be closed thereby through conductor 24,magnetwinding 42, conductors 25 and 25 to the positive main line20.Magnet 40 will thus be energized and will raise its core 43 and itsconnected parts, and contacts 44, 45, 46, and 47 will be moved upagainst contacts 44", 45, 46, and 47 and will close certain cir cuits,which will now be traced. Beginning at main-line conductor 25, a currentwill flow through contacts 47 47 and conductor 25 to brush 11 of motor10, thence through motor-armature 14 and out at brush 12 and byconductor 12 to one side of a starting resistance 70, through thisresistance and by conductor 12 through. the series winding 82 of acontrolling-motor 80, which will be described later, thence by two paths(conductor 83, brake-coil 83, and conductor 83 and conductor 91, switch90, and conductor 92) to contact 46, which is now closed with contact46, to which main-line conductor 24 is connected. Another circuit is atthe same time completed from main-line conductor 25 through contacts 4545 conductors 45 and 15 to the shunt-field 13 of motor 10, through IIOthe field and by conductor 16, contacts 4 1 and 44 to main-lineconductor 24. Thus the motor-armature and field will receive currentfrom the main line, and the armature will begin to rotate in onedirection. The motor may be stopped by bringing the switch-arm 61 backto its central position. If the operator had moved arm 61 of switch tothe right, the result would have been similar; but in this case magnet50 would have been energized and the contacts below it would have beenclosed. This would have supplied the shunt-field of motor 10 withcurrent from the line in the same direction, but the armature withcurrent in the opposite direction, and the motor would have begun torotate in the opposite direction.

It is evident that the reversing-switch contacts may be operated byhand, for if the handle 34 is moved to the right the contacts undermagnet 40 will be closed thereby, or if it is moved to the left thecontacts under magnet 50 will be closed.

It is desirable in starting an electric motor to have its accelerationgradual and proportional to the load it is driving. I will nowdescribe'the apparatus I have invented for automatically accomplishingthis result.

An opposition element in the form of a starting resistance may be placedin the motor-circuit to limit the amount of current which can passthrough the motor. A mechanical device is shown, the purpose of which isto short-circuit this resistance in a number of steps. This devicecomprises a plurality of stationary contacts 91 91, which are connectedtogether and to the lower end of resistance 70 by a conductor 71 of lowresistance. A plurality of movable contacts 92 93 94 95 96 are mountedupon pivoted arms, which will be described presently, and are connectedto various points on resistance 70 by conductors 72, 73, 7 1, 75, and76. Movable contact 92 is insulated from but mounted upon one end of apivoted arm 97, which is pivoted at 97 and the other end of which may beprovided with an antifrictionroller 98. A sliding cam bears upon thisroller 98 and keeps the arm 97 in the position shown in the drawingswhen the apparatus is at rest. The cam 100 may, however, be raised outof contact with roller 98, in which case the arm 97 will move until itscontact 92 rests upon stationary contact 91, and thereby short-circuitsthat portion of resistance 70 which is between conductors 71 and 72. Aspring 99 is sometimes provided to assist this operation. The othermovable contacts are mounted upon similar pivoted arms, and as cam 100is moved up it moves out of contact with other rollers and allows theother movable contacts to be closed against their correspondingstationary contacts and shortcircuits the rest of resistance 7 O inanumber of steps.

A rod 101 extends upward from cam 100 and terminates in a rack 102. Thisrod is guided by a stationary bracket 1.03. A spring 10st bears uponthis bracket and upon cam 100, which may be made hollow, as shown, totake this spring and tends to keep the cam in its lower position againsta stoppiece 105.

S0 designates a secondary or controlling motor of novel construction orarrangement, by means of which mechanical motion is obtainedautomatically in proportion to the voltage and current in an electricalcircuit. It may be an electric motor of ordinary con struction; but Iprefer to have its magnetic held 84 of laminated magnetic material, sothat it may be used as well with alternating as with direct currents. Itis provided with two field-windings, one of which, 81, is connected inshunt with the mains or with the circuit to be controlled, which in thiscase is motor 10, and the other of which, 82, is in series with the samecircuit. These coils are arran ed to oppose each other. The motor has arevoluble armature 85, the coils 86 of which are connected in serieswith shunt field-winding 81. To one end of the armature-shaft isattached a brake-pulley S7, and. to the other end is attached a pinion8S. 1 brake-shoe 87 is arranged to coact with brake-pulley 87. It isnormally held otl' from pulley 87 by a spring 87, but may be broughtinto engagement with the pulley by a brake solenoid S3, acting upon itscore 83".

designates an electromagnetic clutch. It comprises a main portion 111,which is provided with gear-teeth into which pinion 8S meshes, and asecondary portion 112, the whole mounted upon a shaft 113 and supportedby stationary brackets 115. Between the parts 111 and. 112 is anexciting-coil 116, which may be, as shown, in series with the shuntl'ield-winding and the armature. A pinion 114 is mounted upon theclutch-shaft 113 and meshes with rack 102.

The switch 60 may be used only for the purpose of starting and stoppingthe motor 10. If, however, the operator moves the pivoted arm 61 to itsextreme left or right position, he thereby connects stationary segmentalcontact 68 with one of the outer ones of stationary contacts 69, whichwhen either side of the reversing-switch 31 is closed connects shuntfield-wimling S1, armature S5, and clutch-winding 116 across the line. Iwill suppose the operator has moved the switch-arm 61 to the left andwill trace these circuits. Beginning at main-line conductor 25 a currentwill flow through contacts 47 17, conductors 25 25", contact-plate 64,stationary contact 69, conductor 69", through clutch-winding 1.16, shuntfield-winding S 1, armature 85, conductor 85, brake-coil S3, andconductor S3 to and through contacts 16 46 to n1ainline conductor 24.The

shunt field-winding and the armature of motor 80 will thus be energizedin proportion to the voltage between the mains 21. It has already beenshown that the current passing through armature 14 of motor 10 alsopasses through series field-winding 82. The two opposing field-windingsare so proportioned that when the current passing through motor 10 isits normal starting-current the two op osing field-windings willneutralize each ot 1er, and the armature 85 of motor will remain atrest. As the armature 14 begins'to rotate and to thereby reduce theamount of current passing through it the el'lect of series field-winding82 will be reduced, and the shunt field-winding will energize the fieldsof motor 80 a su'l'licient amount to cause armature to rotate in adirection to raise cam 100. This it will do through the mechanismalready described and the electromagnetic clutch 110, which is nowenergized. The movement of cam causes some of resistance 70 to beshort-circuited, which allows more currentto pass through series winding82 and motor 10. The e'liect of series winding 82 will then be tocounteract the ell ect of shunt field-winding 81 to retard or stop therotation of armature 85 or to cause it to rotate in the 0 pcsitedirection if the current in series 'ieldwinding 82 is suflicieiitlystrong. This of course will check the upward movement of cam 100 or mayeven cause it to be driven down again. As the motor accelerates thisoperation will be repeated until all of resistance 70 has been cut out.The acceleration of motor 10 will be proportional to the load it isdriving, which in the drawings is represented by a shafting 17,connected to the motor by a belt 18. It is evident that this arrangementwill automatically control the supply-current to the motor in proportionto its acceleration and that this automatic control depends for itsaction upon the voltage supplied to the motor and upon the currentconsumption of the motor and that it does not act upon or materiallyaffect the voltage from'the source of supply.

Electric motors such as are used on railway-cars, elevators, and insimilar service are usually capable of standing an overload; In suchcases it is not desirable to have an excessive current in seriesfield-winding 82 drive armature 85 backward. and cause it to insert moreof resistance 70* in the main motor circuit. T o prevent this, a brakesolenoid 83 may be provided in the main motor-circuit, which will pulldown upon its core 83 and apply brake-shoe 87 to pulley 87 when itscurrent reaches an amount greater than that necessary to neutralize'theeilect of shunt field-winding 81. This will prevent the armature 85being driven back- Ward unless motor 10 is'gettmg an excessive overloadof current, in which case the brake 87 87 will slip. A switch 90,arranged to connect contacts 91 and 92, which are connected to eitherside of brake-coil 83 by conductors 91 and 92, may be provided toshort-circuit coil 83 and render the brake inoperative when desired.

Fig. 3 is a modification of a detail of 0011- struction. In this casethe rod 101, which is actuated by pinion 114 in one direction and byspring 104 in the other direction, is connected by a link 105 to apivoted arm 106, which slides over stationary contacts 91, to whichresistance 70 is connected, and thereby controls the current to armature14.

It is evident that an operator may insert more or less of resistance 69in circuit with shunt field-winding 81 at will. Thus while he cannotincrease the action of motor 80 he may control its action, retard it anydesired amount, or entirely prevent its action. When plate 64 is movedoff from contacts 69, the clutch becomes denergized, as well as theshunt field-winding and armature of motor 80, and spring 104 will act toimmediately return cam 100 to its original position and to insert all ofresistance 70 in the motor-circuit again.

Fig. 4 illustrates another method whereby the motion obtained by pinion114 and spring 104 may be utilized to control an electric motor. 1n thiscase rod 101 is mechan ically connected to shift the brushes 11 and 12of a motor.

The controlling system herein shown and described is applicable toalternating-current as well as to direct-current systems. This may beseen by an examination of Fig. 2, in which 10 designates analternating-current motor and the circuits are somewhat modified to beapplied to the, control of such a motor, but which is similar to Fig. 1in nearly every other respect.

This invention is applicable to many other uses than those herein shownand described. I have shown it applied to a motor-starting system, asthis is one of its advantageous uses.

' The controlled motor may be connected to run elevators, cranes,mill-tables, or railroadcars' or to any similar use where it"i'sdesirable to have a gradually-increasing current automatically appliedto the motor and a current the amount of which may be controlled by anoperator, but which'c'annot be increased beyond a safe amountby-hiscarelessness. It. may of course also be used in many otherconnections where it is desired to automatically or semiautomaticallycontrol the flow of an electric current.

It sometimes happens that in Startingelectric motors the fluctuations ofcurrent, due to cutting out of starting resistance, becomesconsiderable. A sudden inrush ofcurren t might cause motor'80 to driveback cam 100 and insert the part of resistance 70 which it voltagepractically constant in value, a circuit connected therewith, a motorarranged to control the current in said circuit, said motor having anarmature, a winding for said armature, and two opposing field-windings,one of which is in shunt with said circuit and the other of which is inseries with said circuit.

2. A source of electrical supply having a voltage practically constantin value, a circuit connected therewith, a motor arranged to control thecurrent in said circuit, said motor having two opposing field-windings,one of which is energized by the voltage of said source of supply andthe other of which is energized by the current in said circuit and arotatable armature for the motor.

3. A source of electrical supply having a voltage practically constantin value, a circuit connected therewith, means for varying the currentin said circuit, a motor arranged to actuate the current-varying means,said motor having an armature-winding, two opposing field-windings, oneof which fieldwindings is in shunt with said circuit and the other ofwhich is in series with said circuit.

4; A source of electrical supply having a voltage practically constantin value, a circuit connected therewith, means for varying the currentin said circuit, a motor arranged to actuate the current-varying means,said motor having two opposing field-windings, one of which is in shuntwith said circuit and the other of which is in series with said circuit,and a rotatable armature connected to said current-varying means.

5. A source of electrical supply having a voltage practically constantin value, a circuit connected therewith, means for varying the currentin said circuit, a motor arranged to actuate the current-varying means,said motor having two opposing field-windings, one of which is in shuntwith said circuit and the other of which is in series with said circuit,and a rotatable armature connected to said current-varying means andcontrolled by the current in said field-windings.

6. A source of electrical supply having a voltage practically constantin value, a circuit connected therewith, means for varying the currentin said circuit, a motor arranged to actuate the current-varying means,said motor having two opposing fieldavindings,

- one of which is in shunt with said circuit and the other of which isin series with said circuit, and a rotatable armature having coils, saidcoils arranged to be supplied by current 3 proportional in amount to thevoltage of said l source of supply.

7. A source of electrical supply, a circuit connected therewith, meansfor varying the current in said circuit, a motor arranged to actuate theciurent-varying means, said motor having two opposing field-windings,one of which is in shunt with said circuit and the other of which is inseries with said circuit; and a rotatable armature having coils, saidcoils arranged in series with said shunt-connected field-winding.

8. A source of electrical supply having a voltage practically constantin value, a circuit connected therewith, means for varying the currentin said circuit, a motor arranged to actuate the current-varying means,said motor having an armature and two fieldwindings, one of whichwindings is in shunt with the circuit and has a tendency when onergizedto cause the motor to rotate in one direction, the other of whichwindings is in series with the circuit and has a tendency when energizedto cause the motor-armature to rotate in the opposite direction.

9. A source of electrical supply, a circuit connected therewith, meansfor varying the current in said circuit, a motor arranged to actuate thecurrent-varying means, said mo tor having an armature and twofield-windings, one oi which windings is in shunt with the circuit andhas a tendency when energized to cause the motor-armature to rotate inone direction, the other of which windings is in series with the circuitand has a tendency when energized to cause the motor-armature to rotatein the opposite direction, and a brake in series with said seriesfield-winding arranged to prevent the rotation of the armature under theinfluence of said series field-winding.

10. A source of electrical supply, a circuit connected therewith, meansfor varying the current in said circuit, a motor arranged to actuate thecurrent-varying means, said motor having an armature and twofieldwindings, one of which windings is in shunt with the circuit andhas a tendency when energized to cause the motor-armature to rotate inone direction, the other of which windings is in series. with thecircuit and has a tendency when energized to cause the motor-armature torotate in the opposite direction, a brake in series with said seriesfield-winding arranged to prevent the rotation of the armature under theinfluence of said series field-winding, and means arranged to rendersaid brake inoperative.

11. A source of electrical supply, a circuit connected therewith, meansfor varying the current in said circuit, a motor arranged to actuate thecurrent-varying means, said motor having an armature and twofieldwindings, one of which windings is in shunt with the circuit andhas a tendency when energized to cause the motor-armature to rotate inone direction, the other of which windings is in series with the circuitand has a tendency when energized to check the rotation of themotor-armature under the in fluence oi the shunt field-winding.

12. A source of electrical supply having a voltage practically constantin value, a circuit connected therewith, means for varying the currentin said circuit, a motor arranged to actuate the current-varying means,said motor having a'rotatable armature of laminated magnetic material, afield of laminated magnetic material and two opposing fieldwindings, oneof which is in shunt with said circuit and the other of which is inseries with said circuit.

13. A source of electrical supply, a circuit connected therewith, meansfor varying the current in said circuit, a motor having two opposingfield-windings, one of which is in shunt with the circuit and the otherof which is in series with the circuit, and a rotatable armature; and amagnetic clutch arranged to connect said armature to said currentvaryingmeans.

14. A source of electrical supply, a circuit connected therewith, meansfor varying the current in said circuit, a motor having two opposingfield-windings, one of which is in shunt with the circuit and the otherof which is in series with the circuit, and a rotatable armature havingcoils; and a magnetic clutch having an exciting-coil, said clutcharranged to connect said armature to said ourrent-varying means; saidshunt field-wind. ing, armature-coils and clutch-exciting coil being inseries with each other.

15. A source of electrical supply, a circuit connected therewith, amotor arranged to control the current in said circuit, said motor havingan armature-winding two opposing field-windin s, one of whichfield-winnings is in shunt with said circuit, the other of which is inseries with said. circuit, and manuallyactuated means for controllingsaid motor.

16. A source of electrical supply, a circuit connected. therewith, meansfor varying the current in said circuit, a motor arranged. toautomatically actuate the current-varying means in proportion to thecurrent in said circuit and the voltage of said source of supply, saidmotor having two opposing fieldwindings, one of which is in series withsaid circuit, the other of which is in shunt with said circuit, arotatable armature and a manually-operated switch arranged to controlthe action of said motor.

17. A source of electrical supply having a voltage practically constantin value, an electric circuit, an opposition element therein, and anelectric motor arranged to automatically remove the opposition elementfrom the circuit, said motor having two opposing field-windings, one ofwhich is in shunt with said circuit, the other of which is in serieswith the circuit, and a rotatable armature.

18. A source of electrical supply having a voltage practically constantin value, an elec tric circuit, an opposition element therein,mechanical means for controlling the opposition element, a motor havinga revoluble armature connected to said mechanical controlling means,said motor having two opposing fiel ,lwindings, one of which is in shuntwith said circuit and the other of which is in series with said circuit.

19. An electric circuit, an opposition element therein, mechanical meansfor controlling the opposition element, an electric motor having arevoluble armature, and an electromagnetic clutch arranged. to connectand disconnect said armature to and from said mechanical controllingmeans, said motor having two opposing fieldwindings, one of which is inshunt with said circuit and the other of which is in series with saidcircuit.

20. A source of electrical supply having a voltage practically constantin value, a inotor, means for automatically controlling the accelerationof the motor, said means comprising a secondary motor having twoopposing field-windings, one of which is in shunt with said first motorand the other of which is in series with said first motor, and arotatable armature.

21. A source of electrical supply having a voltage practically constantin value, a motor, a starting-switch therefor, means for automaticallycontrolling the acceleration of the motor, said means comprising asecondary motor having a rotatable armature and two opposingfield-windings, one of which is in shunt with said first motor and theother of which is in series with said first motor.

22. A motor, a reversing-switch therefor, means for automaticallycontrolling the acceleration of the motor, said means comprising asecondary motor having two opposing field-windings, one of which is inshunt with said first motor and the other of which is in series withsaid first motor.

23. A motor, an electrically-actuated reversing-switch therefor, meansfor automatically controlling the acceleration of the motor, said meanscomprising a secondary motor having two opposing field-windings, one ofwhich is in shunt with said first motor and the other of which is inseries with said first motor, and a manually-operated switch arranged tocontrol the reversing-switch.

24. A motor, an electrically-actuated reversing-switch therefor, meansfor. automatically controlling the acceleration of the motor, said meanscomprising a secondary motor having two opposing field-windings, one ofwhich is in shunt with said first motor and the other of which is inseries with said first motor.

25. A motor, an opposition element in the ITS motor-circuit, means forgradually cutting said opposition element out of the motor-circuit inproportion to the acceleration of the motor, said means comprising asecondary motor having two opposing field-windings, one of which is inshunt with said first motor, and the other of which is in series withsaid first motor.

26. A motor, an electrically-actuated reversing-switch therefor, anopposition element in the motor-circuit, means for gradually cuttingsaid opposition element out of the motor-circuit in proportion to theacceleration of the motor, said means comprising a secondary motorhaving two opposing fieldwindings, one of which is in shunt with saidfirst motor, and the other of which is in series with said first motor,and a manually-operated switch arranged to control the reversingswitch.

27. A motor, an electrically-actuated reversing-switch therefor, anopposition element in the motorcircuit, means for gradually cutting saidopposition element out of the motor-circuit in proportion to theaccel'er ation of the motor, said means comprising a secondary motorhaving two opposing fieldwindings, one of which is in shunt with saidfirst motor, and the other of which is in series with said first motor,and a manually-open ated switch arranged to control the reversingswitchand to retard the action of the secondary motor at will.

28. A motor, a resistance in the motor-circuit, mechanical meansarranged to shortcircuit the resistance in a number of steps, asecondary motor having a revoluble armature connected to said mechanicalmeans, said secondary motor having two opposing field-windings, one ofwhich is in shunt with said first motor, the other of which is in serieswith said first motor.

29. A motor, a resistance in the motorcircuit, mechanical means arrangedto shortcircuit the resistance in a number of steps, a secondary motorhaving a revoluble armature, an electromagnetic clutch arranged toconnect said armature to said mechanical means, said secondary motorhaving two opposing field-windings, one of which is in shunt with saidfirst motor, the other of which is in series with said first motor.

30. A motor, a resistance in the motor-circuit, mechanical meansarranged to shortcircuit said resistance in a number of steps, asecondary motor arranged to actuate said mechanical means in onedirection, an electromagnetic clutch for connecting or disconnecting thesecondary motor to or from said mechanical means, and a spring foractuating the mechanical means in the opposite direc tiou, saidsecondary motor having two opposing field-windings, one of which is inshunt with said first motor and the other of which is in series withsaid first motor.

31. A motor, an electrically-actuated reversing-switch therefor, aresistance in the motor-circuit, mechanical means arranged toshort-circuit said resistance in a number of steps, a secondary motorarranged to actuate said mechanical means in one direction, anelectromagnetic clutch for connecting or disconnecting the secondarymotor to or from said mechanical means, a spring for actuating themechanical means in the opposite direction, said secondary motor havingtwo opposing field-windings, one of which is in shunt with said firstmotor and the other of which is in series with said first motor, and amanually-operated switch arranged to control the reversing-switch, theelectromagnetic clutch and the action of the secondary motor.

32. A motor, a reversing-switch therefor, electromagnets havinglaminated frames, for the reversing-switch, a resistance in themotor-circuit, mechanical means arranged to short-circuit the resistancein a number of steps, a secondary motor having a revoluble armatureconnected to said mechanical means, said secondary motor having twoopposing field-windings, one of which is in shunt with said first motor,the other of which is in series with said first motor.

33. A motor, a reversing-switch therefor, electromagnets havinglaminated frames, for the reversing-switch, a resistance in themotor-circuit, mechanical means arranged to short-circuit the resistancein a number of steps, a secondary motor having a revoluble armatureconnected to said mechanical means, said secondary motor having fieldsof laminated magnetic material and two opposing field-windings, one ofwhich is in shunt with said first motor, the other of which is in serieswith said first motor.

34. A motor, a reversing-switch therefor, electromagnets having framesand cores of laminated magnetic material for the reversing-switch, aresistance in the motoreircuit, mechanical means arranged toshort-circuit the resistance in a number of steps, a secondary motorhaving a revoluble armature connected to said mechanicalmeans,saidsecondary motor having fields of laminated magnetic material and twoopposing field-windings, one of which is in shunt with said first motor,the other of which is in series with said first motor.

35. A motor, a reversing-switch therefor, electromagnets having framesand cores of laminated magnetic material, for the reversing-switch, aresistance in. the motor-circuit, a mechanical device arranged toshort-circuit the resistance in a number of steps, a secondary motorarranged to actuate said mechanical device in one direction, anelectromagnetic clutch for connecting or disconnecting the secondarymotor to or from said mechanical device, a spring arranged to actuatethe mechanical device in the opposite direction; said secondary motorhaving fields of laminated magnetic material and two opposingfield-windings, one of which is in shunt with said first motor, theother of which is in series with said first motor and amanually-operated switch arranged to control the reversing-switch, theelectromagnetic clutch and the action of the secondary motor.

36. A source of electrical supply, a circuit connected therewith, amotor arranged to control the current in said circuit, said motor havingan armature with a winding, a fieldwinding on the motor, said.armature-winding and field-winding being in shunt with the circuit,another field-winding on the motor in. series with said circuit, saidfield-windings being arranged to create a variable magnetic field in themotor varied in strength and direction according to the current in saidcircuit and the voltage across said circuit.

37. A source of electrical supply, a circuit connected therewith, amotor arranged to control the current in said circuit, said motor havingan armature with a winding, a fieldwinding on the motor, saidarn1aturewind ing and field-winding being in shunt with the circuit,said shunt-winding being arranged to create a magnetic field in themotor, proportional in strength to the voltage across the circuit,another field-winding on the motor in series with the circuit, andarranged to neutralize the effect of the shunt field-winding inproportion to the current passing through said circuit.

38. A source of electrical supply, a circuit connected therewith, amotor arranged to control the current in said circuit, said motor havinga revoluble armature, an armaturewinding, a field-winding in shunt withsaid circuit, and a field-winding in series with said circuit; saidfield-windings being arranged to oppose each others infiuence on thespeed and direction of rotation of the armature.

39. A source of electrical supply, a circuit connected therewith, amotor arranged to control the current in said circuit, said motor havinga revoluble armature having a winding, and two opposing field-windings,and means for charging said armature-winding and said two field-windingssimultaneously;

40. A source of electrical supply, a circuit connected therewith, amotor arranged to control the current in said circuit, said motor havinga revoluble armature having a winding, and two opposing field-windings,and means for charging said armature-winding and said two field-windingssimultaneously from the source of supply,- the connections of saidmotor-windings being so arranged that the speed and direction ofrotation of the armature is automatically controlled by variation ofcurrent in the circuit.

41. A source of electrical supply, a circuit connected therewith, amotor arranged to control the current in said. circuit, said motorhaving an armature and an armature-winding, and two op osingfield-windings, one of which is excited by a current of practicallyconstant value, the other of which is excited by a variable currentpassing through said circuit.

42. A source of electrical supply, a circuit connected therewith, amotor arranged to control the current in said circuit, said motor havingan armature and an armature-winding, and two opposing fieldwindings, oneof which is excited by a current of practically constant value, theother of which is excited by a variable current passing through saidcircuit, the magnetic effect of said two fields being arranged tocontrol the speed and direction of rotation of the motor-armature.

43. A source of electrical supply, a circuit connected therewith, amotor arranged to control the current in said circuit, said motor havingan armature and an armature-winding, and two opposing field-windings,one of which is excited by a current of practically constant value, theother of which is excited by a variable current passing through saidcircuit, the magnetic effect of said two fields being arranged tocontrol the speed and direction of rotation of the motor-armature,

all of said windings being arranged to be charged simultaneously, one ofsaid field- 5 windings being arranged to oppose the effect of the otherfield-winding in proportion to the variation of current in the circuit.

44:. A source of electrical supply, a circuit connected therewith, amotor arranged to control the current in said circuit, said motor havingan armature, an armature-winding, and two field-windings, thearmature-winding and one of the field-windings being connected inseries, and of comparatively high resistance, the other field-windingbeing of comparatively low resistance, said windings arranged to becharged simultaneously, one of said field-windings being arranged tooppose the effect of the other field-winding in proportion to thevariation of current in the circuit.

45. A source of electrical supply, a motor connected therewith, meansfor automatically controlling the current supplied to the motor inproportion to its own acceleration, said means comprising a secondarymotor arranged to actuate the current-controlling means, said secondarymotor having an armaturewinding and two opposing fieldwindings, andmeans for simultaneously charging said windings and said controlledmotor from the source of supply.

46. A source of electrical supply, a motor connected therewith, meansfor automatically controlling the current supplied to the motor inproportion to its own acceleration, said means comprising a secondarymotor ar ranged to actuate the current-controlling means, said secondarymotor having an ar- 1nature-winding and two opposing fieldwindings, andmeans for simultaneously charging said windings and said controlledmotor from the source of supply, and a manually-operated switch arrangedto control the current through the armature-winding and one of thefield-windings of said secondary motor.

47. A source of electrical supply, a motor connected therewith, astarting switch, means for controlling the current supplied to themotor, a secondary motor mechanically connected to thecurrent-controlling means, said secondary motor having anarmaturewinding and a field-winding in shunt with said first motor, asecond winding in series with the first motor and arranged to oppose theefiect of the shunt-winding, and contacts in said starting-switcharranged to simultaneously connect both motors with the source ofsupply.

48. A source of electrical supply, a motor connected therewith, anelectrically-operated reversing-switch, means for controlling thecurrent supplied to the motor, a secondary motor mechanically connectedto the current-controlling means, said secondary motor having anarmattire-winding and a fieldwinding in shunt with said first motor, asecond winding in series with the first motor and arranged to oppose theefiect of the shuntwinding, contacts in said starting-switch arranged tosimultaneously connect both motors with the source of supply, and amanuall -operated switch arranged to control the startingswitch and thearmature-winding and shunt field-winding, and to reduce the current insaid windings at will.

49. A source of electrical supply, a circuit connected therewith,electromagnetic means, comprising a revoluble armature arranged tocontrol the current in said circuit, a brake arranged to check theoperation of said means, the pressure of said brake being proportionalin strength to the amount of current in said circuit.

50. A source of electrical supply, a circuit connected therewith,electromagnetic means comprising a revoluble armature arranged tocontrol the current in said circuit, an electricalljy -actuated brakearranged to mechanically act upon and thereby control the speed of saidarmature, a circuit for said brake, said circuit being in series withthe controlled circuit.

51. A source of electrical supply, a motor connected therewith, meansfor varying the current in said motor, electromagnetic means comprisinga rotatable armature arranged to automatically actuate thecurrent-Varying means in proportion to the acceleration ol the motor,and a brake arranged to control the electromagnetic means, thecontrolling effect of said brake being proportional in strength to thecurrent in the motorcircuit.

52. A source of electrical supply, a motor connected therewith, meansfor automatically controlling the current in said motor in proportion toits own acceleration, electromagnetic means arranged to actuate thecurrent-controlling means, an electrically-actuated brake, circuit forsaid brake, said brake-circuit being in series with the motorcircuit andarranged to ai'l'ect the action of the electromagnetic controllingmeans.

A source of electrical supply, a circuit connected therewith, a motorarranged to control said circuit, said motor having a revoluble armatureand an armature-winding and two field-windings of differentcurrentcarrying capacities, the winding of the least current-carryingcapacity being supplied by current from a slnint-circuit, and arrangedto cause the armature to rotate in one direction, the field-winding ofthe greatest current-carrying capacity being arranged to oppose suchdirection of rotation in proportion to the fluetuation and currentconsumption in said circuit.

54. A source of electrical supply, a circuit connected therewith, amotor arranged to control the circuit, said motor having a rotatablearmature and an armattire-winding, and a field of laminated magneticmaterial, adapted for director alternating currents, and having twoopposing field-windings of different current-carrying capacities, one ofsaid field-windings being in shunt with the circuit, the other of saidwindings being in series with the circuit.

55. An electrical controller adapted for direct or alternating currents,said controller comprising an electrically-actuated reversing-switch,magnets haying fields of laminated magnetic material for saidreversingswitch; and a motor having fields oi laminated. magneticmaterial and a shunt-winding upon said fields, and a series winding alsoupon said fields, and. arranged to oppose said shunt-winding.

In testimony whereof I have signed my name to this specification in thepresence of two subscribing witnesses.

DAVID LARSON.

\Vitnesses:

ADRIAN M. POTTER, Ennns'r W. Mansnatt.

